Bristle articles in the present context not only means brushes, brooms, paint brushes, etc. having a conventional construction, i.e., with a handle, grip, etc. and a bristle carrier covered with bristles, but also bristle elements of any type in which, for example, the plastic bristles are joined together at one end by melting to form a bristle strip, the bristle group, etc. For the supply of bristles to the bristle article production station to fundamental process have been proposed. First, the bristle bundle can be supplied in the form of an endless strand and are only cut to the desired length directly at the production station and, optionally, after producing the bristle article. Secondly, it is possible to work with so-called short cuts, for example, prior to the production station, the bristles are cut to the desired length, optionally, with a processing tolerance and then the cut bristle are supplied in bundles to the production station.
When processing cut-to-length bristles, the bristles are placed substantially in parallel in a shaft-like magazine, which normally has two parallel walls spaced with the bristle length. One or more holes are provided in one wall in a lower region of the magazine near the bottom of the magazine whereby it is possible to remove the bristles through the wall in bristle bundles. This function is fulfilled by bundle grippers in the form of small tubes adapted to be introduced through the opening in the magazine. The bundle gripper immersed in the bristle supply and separate a number of bristles from the remaining bristle supply corresponding to the free cross section thereof. The immersion depth of the bundle gripper is generally somewhat less than the bristle length. After extending the bundle gripper out of the magazine, the bristle bundles located in the bundle gripper and projecting outwards therefrom are brought to the production station. Several problems are encountered in this procedure for forming and receiving bristle bundles. When the bundle is inserted in the magazine, the bristles meeting the opening edge of the bundle gripper are displaced outwards at right angles to a movement direction of the bundle gripper or into the bundle gripper or moved axially in front of the gripper. As a result of the first mentioned effect the bundle gripper takes up a different number of bristles, so that the bundles have different densities. In the case of the axial displacement of bristles, the bristles are placed around the opposite magazine wall, then bent down or rolled in with the consequence that when, during the next operation, the bristles are received in a bundle, the bristles lead to a regular projecting length of bristles on the bundle gripper or may even be rendered unusable due to deformations. Attempts have been made to remove these problems in that the bundle grippers are cut in a sloping manner at their opening (DE 28 49 510, DE 29 22 877, U.S. Pat. No. 3,471,202). Thus, with this construction, during the insertion movement, the entire opening edge of the bundle gripper does not enter the bristle supply over its entire circumference and instead successively with partial regions thereof. As the opening edge has a finite thickness, it is not possible to completely eliminate the aforementioned problems. It is disadvantageous that, as a result of the sloping openings, the bristles are mainly displaced to one side and consequently the degree of filling fluctuates considerably. The other, mainly used construction is a bundle gripper with an opening edge, which is at right angles to the bristles in the magazine and the outer wall is conically tapered towards the opening edge, so that the opening edge ideally is a liner edge. This generally restricts the possibility of the bristles being axially displaced through the opening edge (DE 23 35 468, 25 11 611, 26 46 048, 2 00 146, EP 0 149 996, U.S. Pat. No. 3,563,609). Nevertheless, problems of the aforementioned type still occur. Upon removal of the bundle gripper problems can also occur, in that not all the bristles gripped by the bristle bundle gripper remain and instead stick in the magazine due to frictional forces, or are partly drawn out of the bundle gripper. The more particularly applies with respect to the marginal bristles. The reason for this can be a looser filling or the fact that the bristles do not all engage on termination of the bundle gripper facing the opening, for example, the bristles are located with different lengths in the bundle gripper. Attempts have been made to eliminate this problem, inter alia, in that the wall facing the bundle gripper is constructed as a spring-loaded piston which has a cross section corresponding to the bundle and which moves back into the insertion direction during bundle gripper insertion, for example, the bristles grasped by the bundle gripper can escape in the insertion direction relative the bristle supply. In retracting the bundle gripper there is a follow-up by the piston and, consequently, the bristles follow up by the same length in the bundle gripper (U.S. Pat. No. 3,563,609). Quite apart from the fact that such a magazine has a complicated construction, functional disturbances can occur particularly at the transition between the piston and the magazine wall.
According to another possibility (DE 23 35 468), on inserting the bundle gripper the bristles are compressed, in that the gripper is provided on the inside with a constriction, which is either positioned at the central axial length or at the opening. Although this may well be able to render uniform the degree of filling of the bundle gripper it leads to other disadvantages. As a result of the frictional forces between the bristles increase toward the bundle circumference, the bundle gripper is not uniformly filled in depth. There is also a risk that, due to these increased frictional forces the circumferential bristles will project further in the marginal area and will be pushed onto the facing magazine bottom and bent.
Another measure for cleanly cutting the bristles in the bundle for the supply involves providing the bundle gripper externally with deflectors, so that the frictional forces between the cut off bristles and the bristle supply are reduced. (DE 23 35 468). It has also been found that, within the magazine, the bristles should be present with a more uniform looser packing. In order to achieve this bristle-parallel, constructions are provided within the magazine (EP 0 289 687), which take up part of the pressure of the bristle supply above the bundle gripper and ensure a looser backing in the vicinity of said gripper. However, the danger exists that the packing will be completely non-uniform in a vicinity of the bundle gripper. Upon withdrawing the bundle gripper with the cutoff bristle bundles, the bristle adjacent to the gripper can be moved in the removal direction and may possibly be withdrawn from the magazine, thereby leading to problems during the next operation. Therefore, if possible the bristle end should be in one plane at the insertion side. Similar effects occur on inserting the bundle gripper, in that the bristles are moved toward the opposite side. To avoid this it has been proposed in EP 0 289 687, to construct the magazine wall facing the insertion side as an oscillating or vibrating plate which acts substantially axially on the bristle ends and all of the bristle supply in the vicinity of the bundle gripper is compressed on the facing magazine wall. The bristle located in the bundle gripper should be vibrated into the magazine wall. As individual projecting bristles, due to their flexibility, can easily be placed around in front of the other bristle ends during the axial action and, due to the compression on the opposite wall, bristles can also be deformed there, this procedure does not completely obviate the indicated problem.
Finally, any problem occurring the magazine leading to the bristles project into a varying length at the bundle gripper or to a fluctuating degree of filling, can also have a disadvantageous effect in the subsequent production of the bristle articles. This more particularly applies if the bristles are joined to the bristle carrier or shaped into a bristle element by a thermal process, such as welding, melting, injecting, etc.